package com.fzy.leetcode.editor.cn;
//2023-03-16 09:56:03
//用两个栈实现一个队列。队列的声明如下，请实现它的两个函数 appendTail 和 deleteHead ，分别完成在队列尾部插入整数和在队列头部删除整数的
//功能。(若队列中没有元素，deleteHead 操作返回 -1 ) 
//
// 
//
// 示例 1： 
//
// 
//输入：
//["CQueue","appendTail","deleteHead","deleteHead","deleteHead"]
//[[],[3],[],[],[]]
//输出：[null,null,3,-1,-1]
// 
//
// 示例 2： 
//
// 
//输入：
//["CQueue","deleteHead","appendTail","appendTail","deleteHead","deleteHead"]
//[[],[],[5],[2],[],[]]
//输出：[null,-1,null,null,5,2]
// 
//
// 提示： 
//
// 
// 1 <= values <= 10000 
// 最多会对 appendTail、deleteHead 进行 10000 次调用 
// 
//
// Related Topics 栈 设计 队列 👍 717 👎 0

import java.util.*;

class YongLiangGeZhanShiXianDuiLieLcof {
    public static void main(String[] args) {
        //创建该题目的对象方便调用
        CQueue solution = new YongLiangGeZhanShiXianDuiLieLcof().new CQueue();
    }
    //leetcode submit region begin(Prohibit modification and deletion)
class CQueue {

    private Deque<Integer> pushStack;
    private Deque<Integer> popStack;

    public CQueue() {
        pushStack = new ArrayDeque<>();
        popStack = new ArrayDeque<>();
    }
    
    public void appendTail(int value) {
        pushStack.add(value);
    }
    
    public int deleteHead() {
        pushtopop();
        if(popStack.isEmpty()){
            return -1;
        }
        int val = popStack.pop();
        while (!popStack.isEmpty()){
            pushStack.add(popStack.pop());
        }
        return val;
    }
    public void pushtopop(){
        while (!pushStack.isEmpty()){
            popStack.add(pushStack.pop());
        }
    }
}

/**
 * Your CQueue object will be instantiated and called as such:
 * CQueue obj = new CQueue();
 * obj.appendTail(value);
 * int param_2 = obj.deleteHead();
 */
//leetcode submit region end(Prohibit modification and deletion)

}